What are the code 975mc mean on white gold jewelry?

The code "975mc" on white gold jewelry indicates that the piece is made of 97.5% pure gold, which is equivalent to 23 karats. The "mc" often stands for "millésime" or "millesimal," referring to the method of specifying the gold purity. This high level of purity suggests that the jewelry is of superior quality, though it may be alloyed with other metals to achieve the white gold appearance.